Subelement L: L – Installation, Maintenance & Repair— Topic 74: Indicating Meters
Question 3-74L6
Element 3 (GROL)What instrument may be used to verify proper radio antenna functioning?
Explanation
An SWR (Standing Wave Ratio) meter is the primary instrument used to verify proper antenna functioning. It measures the impedance match between the radio, transmission line, and antenna. A low SWR (ideally 1:1) indicates that the antenna is resonant and efficiently accepting power from the radio to radiate into the air, which is the definition of proper functioning. A high SWR means a significant portion of the power is reflected back, indicating a mismatch and poor antenna performance.
A digital ohmmeter (A) measures DC resistance, which doesn't reflect the antenna's impedance at RF frequencies or its radiation efficiency. A frequency meter (B) verifies the radio's output frequency, not the antenna's performance. Using a different radio (D) might confirm basic operation, but provides no quantitative data on the antenna's tuning or efficiency.
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